Pirelli again created the headlines at a grand prix yesterday, when motorsport director Paul Hembery pulled out of a post-practice press conference on the advice of the company’s lawyers.

The Italian tyre manufacturer has been beleaguered ever since they organised a test after the Spanish Grand Prix last month in which Mercedes participated on their behalf, supposedly testing 2014 tyres.

A lively debate was in store in the conference as McLaren’s Martin Whitmarsh, Ferrari’s Stefano Domenicali and Red Bull’s Christian Horner, were expected to grill Hembrey and fellow team principal, Ross Brawn of Mercedes, about the test, in the wake of the governing body FIA decreeing last Wednesday that the Anglo-German team must face an official investigation. Hembrey, however, withdrew minutes before it was due to start.

The investigation was ordered after Red Bull and Ferrari protested against Mercedes’ use of a 2013 car to assist Pirelli in the 1,000km test, something which Lotus team principal Eric Boullier had earlier in the day said breached the rules.

And he believes that when the International Tribunal decide on Mercedes’ fate – a meeting could be convened on 20 June – they will punish the team for breaking sporting regulations. Should the team be found guilty, a range of penalties is open to the tribunal. These range from a heavy fine through deduction of world championship points to exclusion from a race or even the championship. The middle option is the most likely.

“It’s good to have a hearing, parties talking officially, and then we will see the outcome of this,” Boullier said. “But there is clearly a breach somewhere, and then you expect to see a sanction.

“Fundamentally for me there is a big issue, which is a breach of the sporting code. Testing is banned. You have a sporting code and a testing agreement signed by all the teams. Clearly, testing today is key in some way. Limited mileage forces you to change the process by which you design your car, the way you race. For many years performance was just aero [aerodynamics]. Now, you still need aero, but for the first time you need to consider the management of the tyres to make your weekend a success. So by doing testing you have a serious gain of the understanding of the tyres, and that’s something which is not fair.”

Boullier also pointed out that Pirelli’s data on their 2013 tyres was made available last year to every team, and that Lotus [together with Ferrari] chose to optimise their car around the rubber it would run, whereas others chose still to focus more on aerodynamics.

He also said that he had no problem that Ferrari, who also conducted a test in Barcelona with Pirelli and were initially asked to assist in the FIA investigation, had been let off the hook as they complied with the regulations by using a 2011 car, even if it was driven by third driver Pedro de la Rosa.

“I think Ferrari pushed the envelope,” he said, “but they are not in breach. They respected the regulation, and if you do that, then fine. With Pirelli it’s different because they are supposed to be fair and treat everybody equally, which is borderline with their contractual agreement.”

The feeling in the paddock is that the situation with Mercedes needs to be resolved quickly in everyone’s interests, so that the teams can all then sit down with Pirelli and discuss a way forward. “We can still trust them, but we maybe have to sit down again and remind everybody of their needs of the agreement,” Boullier said.

On the track ahead of tomorrow’s Canadian Grand Prix, Fernando Alonso snatched the fastest time from Lewis Hamilton in yesterday’s second practice After Formula One’s most underrated driver, Paul di Resta, had excelled to beat Jenson Button to fastest time in a wet-but-drying morning session, Alonso wound up his Ferrari for a lap of 1min 14.818sec as the track stayed dry throughout the afternoon.

The Spaniard, who could not better seventh place recently in Monaco, said: “We need four or five consecutive races on the podium or close to the podium to recover some of the points we have missed. This weekend, we must score good points.”

Hamilton was happier with the braking performance of his Mercedes, comfortably setting the pace with 1:14.830 before Alonso upstaged him with 1:14.818 as Monaco winner Nico Rosberg managed only fifth on 1:15.249.